The present invention relates to electrical connectors and more particularly to access to telephone system wiring through the subscriber side of a network interface device.
Telephone companies (or “telcos”) typically maintain telephone wiring up to a demarcation point where the telco feed interfaces with the house or premises wiring. The demarcation point is located in a network interface device (NID). The NID has two “sides”—one for the phone company and one for subscriber access. At least the telco-side of the NID terminates in a modular test jack. The test jack comprises normally closed shorting bars that connect inside wiring to the telco feed when no plug is inserted into the test jack. When a plug is inserted into the test jack, the telco feed is disconnected from the inside wiring. In this way, a telephone known to be in working order can be used to test the telco feed while isolating the inside wiring.
Competition for local telephone service subscribers is growing. Broadband service providers offer digital telephone service, which turns voice calls into digital packets for dispatch over a managed IP network. A cable company can now offer cable TV, telephone service and broadband connections on one bill to its subscribers. Other non-telco service providers may provide local telephone service to subscribers using existing inside wiring.
By way of illustration, when a cable subscriber elects to convert from telco-provided local phone service to cable-provided local service, the inside wiring is connected through a cable voice interface device to the cable provider's network. Typically, a cable modem that is either connected to a media terminal adapter (MTA) or is integrated with an MTA is connected to the inside wiring through a wall jack. This installation procedure is sometimes referred to as “backfeeding.” To isolate the cable equipment from the telco feed, the telco feed is disconnected from the inside wiring. Where a NID of the type described above has been provided, the telco feed at the telco side of the NID must be removed or a plug inserted into the test jack.
A modern NID typically has a security monitoring system jack on the subscriber side that allows for the connection of a security monitoring system. An RJ31X jack is commonly used to make this connection.
Typically, the RJ31X jack accepts an eight-conductor RJ45 plug provided by the alarm system provider. FIG. 1 illustrates the wiring configuration of an RJ31X jack 100 as known in the prior art. The telco feed 102 uses contacts 4 and 5 while the inside wiring 104 is connected to contacts 1 and 8. Shorting bars 106A and 106B connect contact J1 to contact J4 and contact J5 to contact J8 when no plug 120 is inserted into jack 100. The insertion of plug 120 into jack 100 causes the shorting bars 106A and 106B to disconnect thus interposing the security system (not illustrated) between the telco feed 102 and the inside wiring 104. During non-emergency conditions, the security system completes the circuits between contacts 1 and 4 and 5 and 8. However, in the event an alarm condition arises, the security system disconnects the inside wiring 104 from the telco feed 102 and “seizes” the telco feed 102 to transmit security data.
The removal of the telco input and the connection of an MTA (not illustrated) to the inside wiring 104 via a wall jack establishes the MTA as the “new” network interface device to the cable system provider network. Where the cable subscriber has a security monitoring system connected to the telco feed through the RJ31X, the “backfeeding” method of installation does not provide a viable connection to the RJ31X alarm network connection point. When an emergency occurs, the security system automatically disconnects from the inside wiring 104 and but has no path through the MTA to the cable system provider's network.
It is possible to avoid this problem by connecting the MTA to the telco feed side of the RJ31X jack (after the telco feed has been disconnected from the inside wiring). Such a connection would establish a connection between the MTA and the network side of the security system. However, there may be legal issues associated with accessing this connection point that make this solution untenable for the cable operator. What is needed is an inexpensive means for connecting an MTA to the network side of a security alarm system without accessing the telco side of the NID while isolating the telco feed from the cable network.